Formerly, when producing a packaging container filled with liquid foods (including fluid products) such as milk, a web-form packaging material composed of a flexible laminated body is longitudinally sealed to become a tubular shape, and while being filled with fluid foods, the tubular packaging material is laterally sealed to produce a packaging container.
An outline of an example of the packaging filling apparatus of the container is shown in FIG. 2. The packaging filling apparatus shown in the example has a thermoplastic layer such as polyethylene in the inside and outside layers, employing laminated packaging material made of aluminum foil, paper and the like. A packaging material web 41, which is wound in a roll-fashion, is wound off and conveyed by a roller in the packaging filling apparatus. A strip tape is spliced to an edge of the packaging material web by a strip tape applicator 43. The packaging material web passes through a sterilization tank 44 to be sterilized. The sterilizing treatment liquid attached on the surface of the packaging material is removed by a squeezing roller and air knife 45.
Then, the packaging material is formed into a tubular shape by a forming roller 46. An overlap is formed by superimposing both ends of the packaging material, and sealing is performed by a longitudinal sealing element 42 along the longitudinal direction of the tube at the overlap in the longitudinal direction. Into the tube, liquid foods are filled from a filling pipe 47. While moving the tube downward by the length corresponding to one packaging container, the tube is sandwiched by a sealing jaw of the transversal sealing apparatus 48 of the induction-heating system and an opposing jaw. A transversal sealing band is formed by performing transversal sealing in the transverse direction, and at the same time, being continuously formed into a first forming body 49. The transversal sealing band of the first forming body is cut in the middle by a cutting apparatus (not shown) such as a knife into a separate first forming body 49 to form the packaging filling container of a final configuration.
In FIG. 3, a detailed partially sectional view of the transversal sealing apparatus 48 and cutting apparatus 32 are shown. In this embodiment, while being moved downward by the length corresponding to one packaging container, a tubular packaging material 1, which is filled with foods, is caught in two pairs of forming flap 31 to be formed into a rough shape of a container, being sandwiched by two pairs of sealing jaws 48a and opposing jaw 48b, forming a transversal sealing band by performing transversal sealing in the transverse direction, and the sealing band of the connected first forming body being cut off in the middle by the knife 33 of the cutting apparatus 32 into a separate first forming body 49.
In the transversal sealing apparatus of an induction-heating system, the packaging material using, for example, aluminum foil performs transversal sealing by induction heating, utilizing its characteristics.
Patent Document 1, Japanese Patent Laid Open 1995-164523
In the case of transversal sealing by the induction-heating of the packaging material using aluminum foil, in order to control the quality of the sealing such as the width of the transversal sealing band, strength of the sealing, the operator checks the condition of the sealing to change the controller of the potentiometer connected with a high-frequency oscillator and modifies the output of the same, if necessary.